This invention relates to an automatic performance device by which automatic performance tones such as automatic bass tones and automatic arpeggio tones are produced at a random or irregular order, thereby to eliminate the monotony in an automatic performance, or to make the automatic performance rich in variation.
An automatic performance device has been known, in the art, in which an automatic performance is carried out according to a performance pattern (such as a bass pattern or an arpeggio pattern) preset. However, since such a conventional automatic performance device carries out only an automatic performance corresponding to a performance pattern of a preset note order, the automatic performance is not rich in variation. This is one of the factors which make the automatic performance dull.
For instance, an automatic bass performance device for automatically producing bass tones is so designed that a reference note (root note) specified by the depression of a key or keys, for instance, in the lower keyboard, and notes (subordinate notes) having predetermined relationships with the reference note are successively, one at a time, selected and produced as tones at preset bass tone production timings and according to a bass pattern representative of note selection information. The bass pattern is determined merely according to a selected rhythm and a specified kind of chord. Therefore, if the selected rhythm and specified kind of chord are maintained unchanged, then the same bass performance is merely repeated according to the bass pattern thus determined. Thus, the bass performance is musically dull or monotonous. This will become more apparent from the part (a) of FIG. 1. In the part (a), the same chord C appears continuously for four measures. For the four measures, a bass performance is repeatedly carried out according to the same bass pattern corresponding to the chord C. Thus, the bass performance is considerably monotonous.